ACID-Base

TEST 06- BASE-ACID

Index:

pH INDICATORS

Phenolphthalein

What is a base?

What is an acid?

• What is an acid?
• Properties of base
• What is a base?
• Properties of a base
• What is pH?
• pH indicators
• What is pOH?
• What is vinegar?
• Neutralization reaction
• Acid-base titration

Phenolphthalein is a chemical compound with the formula C20H14O4 and is often written as "HIn" or "phph" in shorthand notation. Phenolphthalein is often used as an indicator in acid–base titration. For this application, it turns colorless in acidic solutions and pink in basic solutions.

Phenolphthalein is slightly soluble in water and usually is dissolved in alcohols for use in experiments. It is a weak acid, which can lose H+ ions in solution. The phenolphthalein molecule is colorless, and the phenolphthalein ion is pink. When a base is added to the phenolphthalein, the molecule ⇌ ions equilibrium shifts to the right, leading to more ionization as H+ ions are removed.

TEST 06

ACID-Base

In chemistry, bases are substances that, in aqueous solution, are slippery to the touch, taste astringent, change the color of indicators , react with acids to form salts, promote certain chemical reactions (base catalysis), accept protons from any proton donor, and/or contain completely or partially displaceable OH− ions.

These particular substances produce hydroxide ions (OH−) in aqueous solutions. For a substance to be classified as an Arrhenius base, it must produce hydroxide ions in an aqueous solution.

An acid is a molecule or ion capable of donating a hydron (proton or hydrogen ion H+), or, alternatively, capable of forming a covalent bond with an electron pair (a Lewis acid).

In the special case of aqueous solutions, proton donors form the hydronium ion H3O+ and are known as Arrhenius acids. Brønsted and Lowry generalized the Arrhenius theory to include non-aqueous solvents. A Brønsted or Arrhenius acid usually contains a hydrogen atom bonded to a chemical structure that is still energetically favorable after loss of H+.

properties:

What is pH ?

• Bases have a bitter taste
• Feel slippery
• Turn red litmus blue
• Do not react with metals or carbonate

Properties :

PH, short for Potential Hydrogen, is a parameter widely used in chemistry to measure the degree of acidity or alkalinity of the substances.

The pH scale ranges from 0 to 14. Values less than 7 indicate the range of acidity and those greater than 7 that of alkalinity or basicity. The value 7 is considered neutral. Mathematically the pH is the negative logarithm of the molar concentration of the hydrogen ions or protons (H +) or hydronium ions (H3O).

• Bitter-tasting
• React with bases and certain metals to form salts.
• Has a pH less than 7
• It is corrosive

wHAT IS POH?

WHAT IS VINEGAR?

Neutralization reaction

The definition of "pOH" is the negative of the logarithm of the concentration of hydroxide ions in a solution in units of molarity in base 10. It describes how alkaline a solution is; the more alkaline a solution is, the higher the concentration of hydroxide ions in the solution.

Vinegar is a liquid consisting of about 5–20% acetic acid (CH3COOH), water, and other trace chemicals, which may include flavorings. The acetic acid is produced by the fermentation of ethanol by acetic acid bacteria.

A neutralization reaction is when an acid and a base react to form water and a salt and involves the combination of H+ ions and OH- ions to generate water. The neutralization of a strong acid and strong base has a pH equal to 7. The neutralization of a strong acid and weak base will have a pH of less than 7, and conversely, the resulting pH when a strong base neutralizes a weak acid will be greater than 7.

When a solution is neutralized, it means that salts are formed from equal weights of acid and base. The amount of acid needed is the amount that would give one mole of protons (H+) and the amount of base needed is the amount that would give one mole of (OH-). Because salts are formed from neutralization reactions with equivalent concentrations of weights of acids and bases: N parts of acid will always neutralize N parts of base.

ACID-BASE TITRATION

acid + base

Neutralization

Salt + H2O

Acid-Base titration are usually used to find the amount of a known acidic or basic substance through acid base reactions. The analyte (titrand) is the solution with an unknown molarity. The reagent (titrant) is the solution with a known molarity that will react with the analyte.